Valency Study of Vanadium in Stone Coal Ash of Jiangxi Province

Vanadium-bearing stone coal is a new vanadium resource;recovery ofV_2O_5 from the coal has been investigated.It has been found that a satisfactoryextraction of V_2O_5 depends on both the oxidation of V and its reaction with so-dium salt.V in the coal ash of Yushan mainly exists in two oxidation states:98％V(Ⅲ)and2％V(Ⅳ).The distribution of valency of V shows that organicmatter determines V valency at low temperatures,at about470℃,V(Ⅲ)iscompletely oxidized to V(Ⅳ);above500℃,the temperature is the most impor-tant factor for the oxidation of V .At higher temperatures no more V is oxidizedto V(Ⅴ);an equilibrium is established after92％of V is oxidized to V(Ⅴ).The roles of NaCl in the recovery of V_2O_5 from the coal ash were discussed.The best conditions for roasting are temperature750-800℃for1 h.underthe oxidation-chlorination atmosphere.When the ore:NaCl=100:10 by weight,η_roast reaches85.5％.According to the results,a flowsheet for V_2O_5 extrac-tion from coal ash has been proposed.     

绿砷钡铁石在广西的发现

本文研究了在广西德保铜锡矿床氧带化中发现的绿砷钡铁石,给出了它的物理性质、化学成分和晶胞参数等矿物学数据。     

Model studies of the impact of chemical inhomogeneity on SO2 oxidation in warm stratiform clouds

A one-dimensional, time-dependent model of the physics and chemistry of a warm stratiform cloud is used to study the possible impact of chemical inhomogeneity among cloud and raindrops on the oxidation of SO₂ in clouds. The effects of chemical inhomogeneity are examined using two contrasting models: In Model 1 a bulk-solution parameterization is adopted which effectively treats all cloud and raindrops as if they are chemically homogeneous; in Model 2 we allow the cloud and raindrops to have a dichotomous distribution. The dichotomous distribution in Model 2 is simulated by assuming that the two groups of cloud droplets nucleate from two chemically distinct populations of condensation nuclei; one being acidic and the other being alkaline. While the two models yield essentially identical results when the ambient levels of H₂O₂ are greater than the ambient levels of SO₂, the rate of conversion of SO₂ to sulfuric acid and the amount of sulfate removed in the precipitation can be significantly enhanced in Model 2 over that of Model 1 under conditions of oxidant limitation (i.e., H₂O₂ < SO₂). This enhancement is critically dependent upon the fraction of alkaline nuclei assumed to be present in Model 2 and arises from the rapid increase in the aqueous-phase reaction between O₃+S_IV at high pH. Our results suggest that cloud models which adopt a bulk-solution parameterization for cloud droplet chemistry, may underestimate the amount of in-cloud SO₂ oxidation under oxidant-limited conditions.     

Structural relationships between a brown coal and its kerogen and humic acid fractions

A South Australian Tertiary brown coal is fractionated into humic acid and kerogen fractions. These related samples are then subjected to a number of different analytical techniques including infrared and¹³C-Nuclear Magnetic Resonance spectroscopies and pertrifluoroacetic acid oxidation. Structural conclusions are drawn from an integrated consideration of the data. Brown coal aliphatic structure is concentrated in the kerogen and the solvent soluble polar acid fractions. The humic acids are the most aromatic and contain a high degree of hydrogen bonding. Only very minor amounts of long polymethylene chain structures are observed in the humic acids, in complete contrast to the kerogen fraction. Different organic detrital origins are proposed for the coal fractions.     

Importance of the oxidation/maturation pair in the evolution of humic coals

The natural thermal evolution of type III coals (Humic origin) is expressed during diagenesis by a loss of oxygen as CO₂ and H₂O. Other phenomena such as oxidation can cause extensive geochemical modifications and may complicate the effects of simple maturation.Humic coals from the Jurassic in southeastern Utah were studied by elemental analysis, Rock-Eval pyrolysis and infrared spectroscopy. In a van Krevelen diagram (atomic H/C vs atomic O/C), the samples fall within the envelope defined by 860 reference humic coals covering the entire range of diagenesis. Nevertheless, various criteria (geochemical, petrographic, geological and microscopic) cast doubt upon the interpretation that such a distribution of coal composition results from thermal maturation.The same criteria indicate the intervention of redox phenomena. Comparison of our results with those from artificial and natural oxidation shows that these coals were subjected to an oxidation process different from ordinary late alteration. This process was probably due to circulation of highly oxidizing saline water causing oxygen fixation and the transformation of carboxyls into carboxylate anions. The cations that were fixed are oxygenated and certainly contain calcium, but also uranium and perhaps several other cations (V, Mo, Fe...). Emphasis is placed on possible mechanisms that cause such phenomena.     

Methoxy formation in the reaction of CH3O2 radicals with NO

Formation of methoxy (CH₃O) radicals in the reaction (1) CH₃O₂+NOCH₃O+NO₂ at 298 K has been observed directly using time resolved LIF. The branching ratio % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdyMaae% 4qaiaabIeadaWgaaWcbaGaae4maaqabaGccaqGpbGaaeiiaiaabIca% ieqacaWF9aGaa8hiaiaa-nbicaWFGaGaeuiLdqKaai4waiaaboeaca% qGibWaaSbaaSqaaiaabodaaeqaaOGaae4taiaac2facaWFVaGaeuiL% dqKaai4waiaaboeacaqGibWaaSbaaSqaaiaabodaaeqaaOGaae4tam% aaBaaaleaacaqGYaaabeaakiaac2facaqGPaaaaa!4E31!\[\phi {\rm{CH}}_{\rm{3}} {\rm{O (}} = -- \Delta [{\rm{CH}}_{\rm{3}} {\rm{O}}]/\Delta [{\rm{CH}}_{\rm{3}} {\rm{O}}_{\rm{2}} ]{\rm{)}}\] has been determined by quantitative cw-UV-laser absorption at 257 nm of CH₃O₂ and CH₃ONO, the product of the consecutive methoxy trapping reaction (2) % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4qaiaabI% eadaWgaaWcbaGaae4maaqabaGccaqGpbacbeGaa83kaiaa-bcaieaa% caGFobGaa43taiaa+bcacaGFOaGaa83kaiaa+1eacaGFPaGaa4hiai% abgkziUkaabccacaqGdbGaaeisamaaBaaaleaacaqGZaaabeaakiaa% b+eacaqGGaGaaeOtaiaab+eacaqGGaGaa4hkaiaa-TcacaGFnbGaa4% xkaiaa+5cacaGFGaGaa4hiaiabeA8aMnaaBaaajqwaacqaaiaaboea% caqGibWaaSbaaKazcaiabaGaae4maaqabaqcKfaGaiaab+eaaSqaba% aaaa!55AC!\[{\rm{CH}}_{\rm{3}} {\rm{O}} + NO ( + M) \to {\rm{ CH}}_{\rm{3}} {\rm{O NO }}( + M). \phi _{{\rm{CH}}_{\rm{3}} {\rm{O}}} \] is found to be (1.0±0.2). The rate constant k ₁ is (7±2) 10^-12 cm³/molecule · s in good agreement with previous results.     

不同沉积环境成因煤显微组分的有机硫分布

运用扫描电镜能谱微区测试对不同沉积环境成因煤的有机显微组分进行有机硫含量的系统测定，结果表明在不同类型的煤中某一类显微组分的有机硫含量存在明显差异；同一煤中不同亚显微组分的有机硫含量也不同。综合分析发现煤显微组分有机硫含量主要受聚煤环境、组分凝胶化程度、氧化程度的影响，而聚煤环境为主导影响因素。     

The tropospheric distribution of formaldehyde during TROPOZ II

A series of 149 measurements of the HCHO mixing ratio were made between 0 and 10 km altitude and 70° N to 60° S latitude during TROPOZ II. The data show a vertical decrease of the HCHO mixing ratio with altitude at all latitudes and a broad latitudinal maximum in the HCHO mixing ratio between 30° N and 30° S at all altitudes. The measured mixing ratios of HCHO are considerably higher than those expected from CH₄ oxidation alone, but agree broadly with the average latitude by altitude distribution of HCHO derived by a 2D model including emissions of C₁–C₇ hydrocarbons. A number of the regional scale deviations of the measured HCHO distribution from the average modelled one can be explained in terms of the local wind field.     

论晋北石炭二叠系紫色高岭石粘土的成因

晋北地区石炭二叠系煤层中与四号及九号煤伴生的含有机质的软质耐火粘土,即高岭石粘上,俗称紫矸或紫木节。对紫矸的成因过去有两种看法:(1)原生沉积的;(2)后期风化残积“由煤变来的”。笔者认为除这两个因素同时存在外,还与成岩后生作用中有机酸的淋滤和高岭石的重结晶、有序化等有关,尤其是后期风化表生作用使有机质氧化淋滤去SiO_2形成一水软铝石、褪色、溶蚀多孔、质地疏松,形成今日所见紫色高岭石粘土。     

湿地甲烷氧化测定方法及主要控制因子研究综述

湿地甲烷氧化是控制湿地甲烷通量的重要因子.本文对湿地甲烷氧化的测定方法与主要控制因子进行了综述.湿地甲烷氧化的测定方法主要包括未添加甲烷氧化抑制剂培养法和添加甲烷氧化抑制剂培养法.湿地甲烷氧化是诸多因子综合作用的结果,控制湿地甲烷氧化的因子包括湿地生态系统类型、温度、土壤湿度、底物、pH值等.比较而言,底物的浓度(甲烷和氧化性物质)以及土壤湿度是更为重要的环境因子.